Antenna



Jan. 10, 41950 T, T TQRRETTI 2,493,787

ANTENNA Filed March 19, 1946 2 Shets-Sheet l .wm mill f l INVENTOR. TH EODORE T. TORRI-:TTI

BY @www ,9. AJM

ATTORNEY Jan. 10, 1950 T. T. TORRE-m ANTENNA 2 Sheets-Sheet 2 Filed March 19, 1946 INVENTOR.

THEODORE T. TORRETTI ATTORNEY Patented Jan. 10, 1950 ANTENNA Theodore T. Torretti, Trenton, N. J., assignor to the United States of America as represented by the Secretary of War Application March 19, 1946, Serial No. 655,542 1 Claim. ((31.250-33) (Granted under the act of March 3, 1883, as

The invention described herein may be manufactured and used by or for-the Government for governmental purposes, without the payment to me of any royalty thereon.

The present invention relates to antennas, and particularly to adjustable or tunable antennas.

In certain types of electronic equipment, such as radio communication apparatus operable on more than a single frequency, large losses of eiciency occur due to the fact that suitable tunable antennas are not available. Not only should such antennas be tunable so as to obtain maximum-power of propagation and maximum consistency of pattern of propagation, when used as a radiator, and maximum receptivity, when used as a collector, but they should preferably be so constructed mechanically as to be adapted to withstand rigorous service, as in motor vehicle use, and they should also be designed to allow easy replacement of damaged parts.

It is therefore an object of the present invention to provide an antenna which is tunable. It is a further object to provide a tunable antenna which is adapted to vehicular use and the like.

It is a further object to provide a tunable antenna which is also collapsible.

It is still another object to provide a tunable Aantenna wherein the radiator-collector portion thereof, which is most likely to sustain breakage when subiected to hard usage, may be simply and quickly replaced.

It is a further object to provide an. antenna which may be tuned without the use of compensation networks.

It is a further obiect to provide a tunable an- =tenna which is completely mechanical in operation.

These and other obiects and advantages of my present invention, which will be better understood as the detailed description progresses, are obtained in the following manner.

In a preferred embodiment of the present invention I provide an antenna. which includes a radiator-collector made up of a plurality of telescoping tubular sections of approximately equal length, and abase to which the tubular section of largest diameter vis secured. A flexible shaft extends'through the telescoping tubes and has one end secured to the tube of smallest diameter,.and theother. end wound upon a drum preferably rotated by. an' electricfn'iotor;` The uradiatorcollector `is len'gthened:` by rotating the drum by-means of themotor so as to unwind the amended April 30, 1928; .370 O. G. '757) flexible shaft, and it is collapsible by reversing the direction of rotation of the drum.

The said radiator-collector may be tuned by extending it to any length between its collapsed and fully extended positions. Tuning may be controlled by a precalibrated dial or by means of suitable meters which allow maximum efficiency to be checked during use.

In the accompanying specication there is described, and in the annexed drawings shown, what is at present considered a preferred embodiment of the present invention, It is, however, to be understood that said invention is not limited to said embodiment, inasmuch as changes may be made within the spirit and scope of the appended claim.

In said drawings, Figure 1 is an elevational view partly sectioned and partly cut away of a vehicular antenna embodying the present invention;

zo Figure 2 is an enlarged vertical sectional View,

taken along the line 2-2 of Figure 1, the housing of the connection box being shown in elevation;

and

Y Figure 3 is a further enlarged vertical section of the lower portion of the antenna, taken along kthe line 3-3 of Yliigure 2.

Referring now more particularly to the drawings, the antenna illustrated is secured through an aperture in an insulating disk II which in n turn is secured about its periphery to a mounting bracket I3 secured to a motor vehicle (not shown).

The antenna includes a mounting clamp made upof a. lower clamp member I5 and an upper -clamp member II. The upper clamp member I1 is an annulus provided with an outwardly extending clamp-flange I9 at its upper end and a downwardly 'extending tubular flange 2l at its lower end. Said flange 2| is externally threaded.

The lower clamping member I5 is annular in shape and encircles the tubular flange 2l mentioned above and is provided at its lower end with an outwardly extending clamping flange 23,

A flat metal reel bracket 25 which bends downwardly into an arc -at its outer end and 'is se' cured to the lower Aend of the flange 2I by a `lock washer 2 5 and nut 2l` which nut also urges the clamping flanges I9 and 23 together so as toI securely grip therebetween the insulating disk II and an annular dish type insulator 29.

A heavy coaxially disposed helical spring 3| is secured Vto the upper Aend of the upper clamping member il and an annular antenna socket 133 is secured to the upper end of said 'spring 3I.

AA, flexible ltubular sleeve 35, of rubber or the like, encircles the spring 3| and is fastened about the upper clamping member il' and the antenna socket by means of a pair of hose clamps 3l or the like.

A flexible tubular guide 39 extends axially thro-ugh the upper clamping member the spring 3i and the antenna socket 33. Said guide 39 may be made in any suitable manner, such as flexible goose necks as used in adjustable electrical fixtures, or such as the flexible sheath l5", which is described and illustrated in' a pending United States patent application on Flexible members, led in the name of Norman E. Lee, on February 21st, 1946 .and bearing Serial Number 649,448.

Said guide 39 is provided at its lower and upper ends respectively with outwardly extending lower and upper guide 'iianges 4|, 43. Said lower guide ange 4| is gripped between the lower end of the tubular flange 2| and a cup 45 which is threaded on to the lower end of said ilange 2|. The upper guide flange 43 is gripped between an upwardly facing shoulder on the inside of the antenna socket 33 and the lower end of a radiator-collector 4T.

The radiator-collector 41 comprises four telescoping antenna sections 5|, 52, 53, 54 (although any number of such sections may be used). The lowermost antenna section 5l is externally threaded at its lower extremity so as to be threadably joined to the antenna socket 33. The upper end of said section 5| terminates in a tubular throat 55 of slightly lesser diameter. The second telescoping section 52 makes a slidable t inside the throat 55 of said section 5| and its lower end is provided with an outwardly rolled edge 5'! to keep it from separating from the lower section 5| and the said edge 5'.' makes a sliding fit Within the said section 5| below the throat 55 thereof. The upper end of said section 52 is provided with a constricted throat 55 similar to that already described. The next section 53 is a duplicate of the section 52 except that it is of lesser diameter so as to make a sliding Iit within said section 52. tion 54 is of a diameter to make a sliding iit within the section 53 below it and is also provided at its lower end with an outwardly rolled edge 51 (not shown). Said uppermost section 54 need not be provided with a throatJ 55.

A iiexible shaft 59 extends through the guide 39 and all of the antenna sections 5|, 52, 53, 54. The said iiexible shaft 59 may be made in any suitable manner as, for instance, in the conventional manner which comprises a core made up of one or more longitudinally disposed iiexible spring Wires which wire or wires are surrounded by several layers of helically wound spring wire, the successive layers being wound in opposite directions.

The upper end of said flexible shaft 59 is joined to an externally threaded tip 6l, which is locked to the upper end of the uppermost antenna section 54 by means ci a diametrically positioned pin 53. A lock washer 55 and an internallt7 threaded spherical knob 6'! are secured to said tip El. The flexible shaft 59 extends downwardly through an aperture in the cup 45, passes through an arcuate tubular chute 69 into a cylindrical reel housing 'H Where it is wound around the core 'l2 of a rotatable reel 13, the bitter` end of said flexible shaft 59 being secured to said core 12.

The reel housing 7| is held in place below the insulating disk by being secured to the outer The uppermost secend of the reel bracket 25. The shaft 15 of the reel 'i3 is sustained in suitable bearings T6 and may be rotated by means of a slow speed electric motor Ti which operates through a friction clutch T9. Integral with the reel housing 7i, and extending outwardly therefrom, is a connection box 8| through which passes part of the `chute 69.

Within said box 8|, the chute 69 is slotted to admit a pair of contact wheels 83 which are rotatable and provided with circumferential grooves which frictionally grip the iiexible shaft 59 and make electrical contact therewith. An electrical conductor 84 leads from said contact wheels S3 to a conventional coaxial connector 85. Said conductor 84 passes through a conventional thermocouple unit (not shown), which is housed in the connection box 8|, the leads from which unit are connected to the binding posts 8l from which connection may be made to a suitable meter (not sho-wn).

Preferablyy the housing 1|, the chute 59, the connection box 8|, and the reel 13 are of a dielectric material, such as a suitable plastic, to avoid any objectionable electrical effects.

in the operation of the antenna just described, if the motor Il is operated in one direction so as to rotate the shaft l5 '(as shown in Figures v1 and 8) in a counterclockwise direction, the flexible shaft 59 will be fed up the chute 65 and through the guide 39 to the antenna sections 5|, 52, 53. 54. As the upper end of said flexible shaft 59 is vfastened to the upper end of the uppermost telescoping section 54, it will raise said section with it. When said section 54 has extended its maximum amount, the rolled edge 51 at its lower end will catch the constricted throat 55 of the nextV section 53 and thus cause said section to move upwardly with it. As rotation of the motor 'il is continued, telescoping section 52 will likewise be raised until the radiator-collector 47 is extended its maximum length. Should the motor not be stopped immediately, the friction clutch i9 will prevent damage to any parts.

When the motor 'Il is operated in the opposite direction, so as to rotate the shaft l5 (as shown in Figures 1 and 3) in Aa clockwise direction the flexible v'shaft `59 will be Wound up on the reel I3 and thus the sections 5l, 52, 5d will be caused to telescope, one within the other, until the radiator-collector 47 is completely collapsed. Again, the friction clutch 19 will prevent damage to the parts should rotation of the motor 'l1 be continued.

In order to obtain most emcient operation of the radiator-collector 4l, it may be tuned by means of the meter (not shown) mentioned above. Thus it will be extended to that length which the meter indicates gives most satisfactory operation. Tuning may also be accomplished by means of a precalibrated dial (not shown).

The contact wheels 83 are maintained in good electrical contact with the antenna and hence electrical connection is made to the antenna through the coaxial connector 85, the conductor B8, the said wheels 83 and the flexible shaft 59.

The antenna just described is particularly well adapted for motor Vehicle use although it may be used in other installations. The lspring 3|, the flexible tubular sleeve 35 and the flexible guide 39 will allow iiexure of the antenna and will act to 'attenuate vibrations and shocks. The telescoping radiator-collector 41 itself should also preferably have a. limited amount of flexibility for vehicular service.

In the event that, in the use of the antenna just described the radiator-collector 41 sustains any injury, it may be readily removed and replaced by another. This is accomplished by merely removing the knob 61 and pin 53 whereupon the lower antenna section 5| may be unscrewed from the antenna socket 33 and all of the sections 5l, 52, 53, 54 may be slipped upward and removed from the flexible shaft 59. A complete new radiator-collector 41 may then be installed 4by slipping the same over the exble shaft 59, screwing the lower end of the antenna section 5l of greatest diameter into the Iantenna Socket 33 and pinning the upper end of said shaft 5S to the upper end of the antenna section 54 of smallest diameter by means of the pin 53. If only one of the antenna sections 5|, 52, 53, 54 is damaged it may be removed from the radiator-collector 41 and replaced merely by separating said sections.

While there has been described what is at present considered a :preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be -made therein without departing from the invention, and it is, therefore, aimed in the appended claim, to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

In a tunable transmitting antenna system for use with vehicles, a radiator extensible in length for operation over a predetermined range of frequencies, said radiator comprising a plurality of telescoping tubular sections of successively smaller diameters, a flexible shaft extending through said radiator and having one end secured to the teles-coping section of smallest diameter, means Afor `disconnecting said shaft from said smallest section, a flexible base for said radiator to allow lateral displacement thereof, a flexible guide through said base for the exible shaft, a reel upon which the iiexible shaft may be wound, means to rotate the reel in both directions of rotation, said means being calibrated in terms of frequency of operation of said antenna system, a chute to guide the iiexible shaft between the reel and the flexible guides mentioned above, whereby upon the rotation of the reel in one direction the radiator may be reduced in length for operation on a higher frequency, and upon rotation of the reel in the opposite direction the radiator may be increased in length for operation on a lower frequency.

THEODORE 'I'. TORRETTI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,274,883 Brach Mar. 3, 1942 2,299,785 Barrett Oct. 27, 1942 2,211,858 Martin Aug. 20, 1940 2,350,866 Barth June 6, 1944 2,365,886 Lehmann Dec. 26, 1944 2,366,634 Ludwig Jan. 2, 1945 2,388,625 Wagenknecht Nov. 6, 1945 2,391,202 Tellander Dec. 18, 1945 2,419,611 Walsh Apr. 29, 1947 2,420,772 Dalton May 20, 1947 

